This proposed research has the following major objectives: (1) determine the risk of perinatal transmission of Human Immunodeficiency Virus (HIV) to the fetus in women who are asymptomatic but HIV antibody positive, women with AIDS Related Complex (ARC), and women with Acquired Immunodeficiency Syndrome (AIDS); (2) determine the effect of pregnancy on the natural history of HIV infection in women as related to known risk factors; (3) determine the effect of maternal HIV infection on the outcome of pregnancy; (4) determine the natural history of HIV infection in neonates, infants, and children. Additional objectives for which answers will be sought include: (1) to determine the rate of seroconversion from HIV antibody negative to HIV positive in a cohort of nonpregnant women as well as pregnant women who are at risk for acquiring HIV infection; (2) determine the risk and rate of neurodevelopmental defects in HIV negative and positive children being studied; and (3) determine the risks and rate of neuropsychiatric defects in HIV negative and positive women in the study.